<正> Objective: To investigate the development and distribution of phosphate-activated glutaminase like immunoreactive （PAG-LI） neurons in the central pathway of trigeminal proprioception of the rat brainstem. Methods: The immunohistochemitry techniques were used. Results: （1） At embryonic day 17 （E17）

PAG-LI neurons were initially observed in the mesencephalic trigeminal nucleus （Vme）. All PAG-LI neurons were large round neurons with moderate immunostaining. The immunoreactivity grew intense and attained adult-like pattern at P10. （2） Not until postnatal day 10 （P10） did a few PAG-LI neurons appear in the area ventral to the motor trigeminal nucleus （AVM） and area dorsal to the superior olivery nucleus （ADO）

and not until P12 in the dorsomedial part of the subnucleus oralis of the spinal trigeminal nucleus （Vodm） and dorso-medial part of the principal sensory trigeminal nucleus （Vpdm）. As development proceeded

more and more neurons in them were immunostained

and some PAG-LI neurons were detected in the